Sulphur Cinquefoil on the Sweet Marsh in northeast Iowa. USA
Rose family (Rosaceae)
Description: This perennial plant is 1¼–2½’ tall, branching frequently in the upper third of the plant. It is erect in habit, rather than sprawling or stoloniferous. The stems are terete and covered with long white hairs. The alternate leaves are palmately compound. The lower leaves have long hairy petioles and 5-7 leaflets, while the upper leaves are nearly sessile, smaller in size, and often have 3 leaflets. Each leaflet is up to 3½" long and ¾" across; the middle leaflets are larger in size than the side leaflets. Each leaflet is oblanceolate to elliptic and coarsely toothed. The upper stems terminate in flat-topped clusters of flowers. Each flower is about ½-¾" across, consisting of 5 pale yellow petals, 5 hairy green sepals, about 30 stamens with yellowish anthers, and a bright yellow receptacle in the middle with numerous pistils. The spreading petals are obcordate, while the triangular sepals are a little shorter than the petals. The blooming period usually occurs from early to mid-summer and lasts about a month. Each flower produces numerous dark brown seeds, which are somewhat flattened and finely ridged. The root system of a mature plant consists of a shallow crown with coarse fibrous roots; sometimes multiple stems develop from the crown. Reproduction is by seeds.
Cultivation: The preference is full sun, mesic to dry conditions, and a somewhat heavy soil containing clay or gravel. This plant is quite tolerant of alkaline soil.
Range & Habitat: It was accidentally introduced into North America from Eurasia. Habitats include limestone glades, pastures and abandoned fields, vacant lots, gravelly areas along railroads, compacted soil along grassy paths or dirt roads, and weedy meadows. This plant prefers disturbed open areas with alkaline soil.